Rotary motors, pumps and compressors have been known for many years. Generally these devices consist of a housing or casing within which one or more vanes rotate. This is in contrast to those devices which utilize a reciprocating, linearly moving piston. In the case of rotary pumps or compressors, the vanes are rotated by a shaft to pressurize or cause the fluid to flow through the device. In the case of a rotary motor, the opposite occurs. Fluid is introduced into the device under pressure to displace the vanes, which in turn rotates and powers a drive shaft to which the vanes are coupled.
For rotary fluid pumps, the flow of fluid is typically controlled by the rate at which the rotary vanes are rotated. By increasing the speed, more fluid is pumped through the device, while decreasing the speed decreases the amount of fluid pumped. Further, reversing the flow through the device, if possible at all, requires the vanes to be rotated in the opposite direction or requires that the inlet and outlet ports be reconfigured or reversed.
U.S. Pat. No. 5,199,864 discloses a rotary fluid pump that employs vanes rotating within a spherical housing. These devices are highly efficient, and are capable of displacing large quantities of fluid. The flow capacity of these devices, however, is also usually controlled by varying the speed at which the vanes are rotated within the housing. Because this typically requires varying the speed of the motor that rotates the rotary shaft, the flow rate is often difficult to control with any degree of precision. Further, the direction of flow cannot be reversed without modifying the device or reversing the direction of rotation of the drive shaft that drives the vanes.
Other mechanical limitations apply to these prior art devices, such as inadequate removal of heat from the devices, the construction of the vanes to provide improved performance, and methods of securing together the components of the spherical race assembly about which the vanes rotate.
What is therefore needed is a fluid machine or device, such as a rotary motor, pump or compressor, in which the fluid flow through the device can be controlled in an effective, simple and precise manner, and which allows the rotary or drive shaft of the device to be rotated at a generally constant rate or direction of rotation while the direction or rate of fluid flow is varied, and which also addresses the mechanical limitations of the prior art devices.